The Evolution of the Hydrogen Thyratron

By Hans Jucker, Switzerland

The advantages of Hydrogen filling in thyratrons are many. It enables high pulse currents to pass through the tube without causing voltage drops great enough to destroy the cathode, also it can be specifically designed to withstand high voltages.

A second advantage of Hydrogen-filled tube is the short deionization time that is obtained. The only other gas that provides such a short deionization time is Helium, but Helium-filled tubes can not withstand such high voltages as Hydrogen-filled tubes. Experimental work on Hydrogen- as well as Helium-filled tubes was started before and during WWII, but a serious problem connected with the use of these fillings was the gas cleanup, or the disappearance of the gas during operation.

The first Hydrogen-filled thyratrons as the 3C45, 4C35 and 5C22 were developed by the MIT Radiation Laboratory came in use in radar pulse modulators at the end of WWII.

The German AEG company developed 1941/42 the Helium-filled thyratrons S1/3II and S1/6. The S1/3II came in use in the pulse modulator of the German Hohentwiel (FuG 200) airborne and submarine radar.

Interesting paper contribution on this subject, following Hans Juckerís message (pdf):

A couple of months ago I exchanged some correspondences with Colin Pirrie of the Marconi Applied Technologies Ltd. Chelmsford U.K. about the historical background of the Hydrogen- and Helium-filled thyratrons. Colin was so friendly to provide me then his interesting paper: The Evolution of the Hydrogen Thyratron.


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